Opportunistic infection with Candida albicans is a frequent complication in patients with prosthetic heart valves, vascular grafts, long term catheterization, or various immunodeficiency states, either natural or induced by immunosuppressive therapy following organ transplantation. C. allbicans is part of the normal, microbial flora of the gastrointestinal tract, skin and mucous membranes of healthy persons and invades tissues of patients with compromised defense mechanisms. Methods for rapid diagnosis of systemic candidiasis will be developed. Antigens from cytoplasmic material, cell wall fractions and culture filtrate of C. albicans will be used to determine presence of precipitating antibodies in sera from patients with candidiasis, patients at high risk to Candida infections, and healthy individuals. In addition, Candida products will be examined for their ability to inhibit normal cellular defenses, i.e. chemotaxis of neutrophils, phagocytosis of Candida by leukocytes, and the lymphocyte proliferative response. The purpose of these studies is to determine host factors critical for normal defense against fungal invasion and to develop methods for rapid accurate diagnosis of systemic candidiasis.